DESIGN OF SUSPENSION SYSTEMS FOR MEASUREMENT OF HIGH-Q PENDULUMS

Laser interferometer gravitational wave detectors require the use of m assive ultra-high-Q test mass pendulums to minimize thermal noise. The verification of ultra-high Q-factors in pendulums is difficult due to the coupling of support structure recoil losses into the pendulum sta ge. We present a numerical analysis of three different pendulum suspen sion systems to assess their performance. We show that conventional tw o-stage and three-stage suspension systems cannot be expected to verif y Q-factors beyond 10(8) due to recoil losses, but that a twin pendulu m system can allow Q-factors of 10(10) to be observed.